CDC says new test speeds diagnosis of anthrax

Jun 7, 2004 (CIDRAP News) – The Food and Drug Administration (FDA) has approved a new and faster blood test to help confirm a diagnosis of anthrax infection, federal health officials announced today.

The Anthrax Quick ELISA test can identify antibodies to Bacillus anthracis in less than an hour, compared with about 4 hours for previous tests, according to the Centers for Disease Control and Prevention (CDC). The test was developed by Immunetics, Inc., Boston, with funding from the CDC.

"Before FDA approval of the new test, very few laboratories other than the CDC and the US Army had the ability to test blood for antibodies to anthrax," the CDC announcement said. "The new test will be available shortly for use in state and private laboratories."

Immunetics researchers evaluated the blood test by using it on about 35 samples the CDC supplied from anthrax patients, including some of the 22 people who became ill in the letter-borne anthrax attacks in 2001, according to Patty Wilkins, PhD, a research microbiologist in the CDC's Meningitis and Special Pathogens Branch.

"The test was shown to detect 100% of the anthrax patients tested in clinical trials, with less than a 1% chance of false positive results," Immunetics officials said in a news release. The test identified antibodies from people with either inhalational or cutaneous anthrax, and it also detected anthrax-specific antibodies in various animals used as models for human infection, the company said.

Dr. Andrew Levin, president and CEO of Immunetics, said the test detects antibodies to protective antigen, one of the three proteins that make up the toxin produced by B anthracis.

Levin told CIDRAP News the CDC has spent a little over a million dollars on development of the test. Wilkins said the original contract was for about $750,000, and the CDC later provided some additional funds. The contract was awarded following the 2001 anthrax attacks.

Under the contract, the CDC will buy some of the test kits for $5 each to use in its own research, Wilkins said. In addition, it is expected that laboratories in the Laboratory Response Network will be able to buy the test directly from the company, she said. "This is in the process of being negotiated," she said.

Levin said the company hasn't yet determined the commercial price of the test. Any clinical or public health laboratory can use the test without special equipment or training, the Immunetics statement said.

The company said it worked closely with the CDC in developing the test, which is based on the company's proprietary assay technology. "The fact that we were able to move so quickly in development and validation of the test demonstrates how productive such a collaboration between government and industry can be, and we consider the FDA approval a major success for both sides," Levin stated in the news release.